Proposition 2: Keep it simple. We decide what a DRL file is.
Just like an XML file says to hell with the specified encoding, so can we.
Note: All XML files default to UTF-8 encoding, and you can overwrite it in a header in the XML file itself (= self-describing): no need to mess around in the java code.
Same principle: All DRL files are default UTF-8 encoding. Optionally we can define an encoding header later.

I strongly prefer proposition 2. The world has got enough encoding problems.